If any of you read the boxcar bash in this month’s GR, the article mentioned a ‘one cylinder shay’. I didn’t know those existed; thought 3 cyl was the only way they came. Is there a website that discusses the technical details of a shay? Other than U-joints and slip-shafts like my ol’ Massey hay baler had, I can’t see how power was sent from the crankshaft to the trucks. And those would rattle omniously if I crinked a turn too hard!
Les
I don’t recall ever hearing of a “one-cylinder” Shay (maybe it was Ephraim’s initial effort). The Lima-produced Shays were either 2- or 3-cylinder.
You aren’t too far off the mark with your Massey’s PTO; the Shay’s cylinders were mounted vertically, usually (but not always) on the right-hand side. The crankshaft ran longitudinally, about axle-high, and connected to slip-joints and universals which (finally!) attached to shafts on the trucks. Bevel gears on these shafts mated with others on the wheel rims.
Also you could check out “Gearedsteam.com”. Lots of info on Shays, as well as Heislers, Climaxes, Willammettes,…
they didnt, the model was built as a whimsical fancy. There a log on Mylargescale.com.
For geared steam history this is one of the best sites:
Here you go, Les. This tells all about it, including a video at the bottom.
A 1 cylinder shay or ordinary loco is indeed a whimsical beast. It takes at least two cylinders to control which direction an engine will move and to prevent dead centering.
When a drive rod broke on the real thing, they could move if the other drive rod was near the bottom or the top of its driving wheel. If dead center, the best they hope for was being on less than level ground which if steep enough would let them coast enough to get started - hopefully in the right direction.
Art
Bill,
Thanks for that really clear shot of the shay gearing. Finally, at last. Now to go hunt some miter gears… (way down the road). Square shafts, even. U-joint at each end. My, my.
Les
Well, you know, I looked at the thing and thought “That boiler is 'way low down, wonder why?” And, “Prototypically, I suspect that thing’d have a hard time pulling itself, let along a car.” Learnin’ stuff, I yam.
Thanks for the reply.
Les
Thanks for the other addr, Bob.
LEs
Les, you’re right that a ‘one lunger’ can be started with ‘manual intervention’. The little vertical steam engines we played with as kids could rotate either direction IF we ‘helped’ them.
But how big an engine can you help? One could actually lift a VW Beetle back on to the road when stuck in snow, but a Caddilac was a different horse. Hopefully, the little 1 piston shay compares well with the VW.
When a piston is at rest at the end of it’s stroke, it knows not what to do. The quartering (thirding?) of a two or three piston engine eliminates that indecision.
Of course the electric motor you intend to add to the drive system also solves the problem. But a broken main drive rod on a big steam engine could pose quite a problem.
Art
Then just hope it doesn’t break. 